LONDON, Jan 29 (Reuters) - A former tabloid reporter told a London court on Wednesday that Rupert Murdoch's British newspaper arm, News International, had been involved in a conspiracy to cover up phone-hacking and that he had lied about his own role to toe "the company line".

Dan Evans, who has admitted hacking into mobile phone voicemails of dozens of celebrities during his time at Murdoch's News of the World, said he had lied about it both to police and in a civil legal case as part of a widespread company cover-up.

However, the lawyer for Andy Coulson, the paper's former editor and Prime Minister David Cameron's ex-media chief, suggested Evans had only implicated others people in a bid to make a deal with police to avoid prosecution.

Coulson, editor until 2007 and Cameron's head of communications up to 2011, is on trial accused of conspiring to intercept voicemails and authorising illegal payments to public officials, charges he denies.

He has denied any knowledge of hacking and says he could not be expected to know the source of every story in his paper.

"The truth is Andy Coulson knows exactly what went on on his watch," said Evans during more than five hours of often heated exchanges with Coulson's lawyer Timothy Langdale at London's Old Bailey Court.

Evans said his phone-hacking prowess was common knowledge in the newsroom and there was a blasé attitude towards his illegal activities. "The office cat knew," he said.

Evans was arrested in August 2011, a month after Murdoch closed the News of the World amid public anger at revelations of phone-hacking which prompted Cameron to order a broad public inquiry into press ethics.

The 38-year-old admitted he had lied in a statement to London's High Court in 2010 about trying to access the voicemail of interior designer Kelly Hoppen who had sued News International, now known as News UK, after tracing Evans as the source of a failed hacking attempt.

When confronted by a senior figure at News International, he blamed "sticky keys" on his phone, and the firm's lawyers used this as their defence in litigation brought by Hoppen.

Asked why he had agreed to their doing that, Evans said: "I was toeing the line, the party line, the company line."

He later commented: "As far as I was concerned, it (phone-hacking) was so widely known at the paper and covered up so extensively, there was a widespread conspiracy within the organisation."

By late 2011, Evans was considering approaching the police about seeking immunity if he came clean.

Evans said: "I was a very frightened man at the time. I was one person caught between the prime minister, caught between the tabloid world, caught between highly paid lawyers. I didn't know what to do. I'm very sorry for lying at the time."

But Langdale said discussions with detectives revealed immunity would only be possible if he had evidence about other "people at senior levels", saying police had a "shopping list".

"What you were seeking to obtain was a complete immunity from any prosecution for any offence you might admit," Langdale said. "You were ready to do just about anything to get ... immunity."

In the end, the Crown Prosecution Service decided it could not offer him full immunity but offered a deal which would grant him a lesser sentence should he plead guilty.

"SWEEPING STATEMENTS"

Earlier Evans admitted that he was paraphrasing comments by Coulson when he told the court on Tuesday that the former editor had said "brilliant" after listening to a hacked phone call Evans played to him.

"The word came out of my mouth as I was trying to explain the general sense of him being very happy about what had been produced from him," Evans said.

Evans also agreed that his claim that phone-hacking was discussed daily in editorial conference meetings led by Coulson and which he did not attend himself was based on one occasion when a colleague had told him it had been raised.

"Another indication that you are prone to make sweeping statements that are not actually based on fact," Langdale said.

Evans, the fourth News of the World journalist to have admitted phone-hacking charges, replied: "That's not correct."

The trial of Coulson and six others accused of offences relating to the phone-hacking scandal, including Rebekah Brooks the former News International chief, is due to last until May. They deny all charges.

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